The present invention relates to a vibration preventing alloy having a vibration damping ability, and more particularly, to an iron (Fe-Mn) vibration damping alloy having an excellent damping ability with keeping a high strengh and manufacturing method thereof.
Recently, in order to prevent vibration and rumbling sound generated from various machines and instruments such as aircraft, ship, vehicle, machinery, precision machine and the like, using of vibration preventing alloy material is widely spread.
As conventional vibration preventing alloy, Cu-Mn alloy, Ni-Ti alloy, and stainless steel alloy utilizing a twin crystalline transformation have been known.
Such alloys are excellent at adjacent of normal temperature in damping ability, but as they use expensive metals it causes an increasing factor of manufacturing cost, and cold workability is inferior as well as preciseness and complexity are required on manufacturing process in response to respective element.
Further, Al-Zn alloy and cast iron group alloy are in a state of not capable of satisfying a tensile strength as well as hardness value.
On the other hand, a vibration preventing alloy of austenite group being of high Mn steel is known in Japanese laid open patent publication No. 56-258.
This alloy is added with element of chrome, aluminium or Mo, V, Nb, Ti and the like so that it causes an increasing factor of manufacturing cost, and in order to obtain a stable austenite structure, appropriate physical property is required to the austenite such as it requires to closely adjust particularly the contents of carbon (C) and chromium (Cr) among the containing ingredients.
As important forms producing the vibration damping, there are divided into generally three kinds of absorption form, resonance form and historical form.
Damping by absorption form does not depend on an amplitude of vibration but depends on a vibrating frequency numbers, and it is not so greatly considered in view of vibration preventing.
Resonance form does not depend on an amplitude of vibration in a damping ability as same as the absorption form but depends on a vibration frequency numbers, and in this case, maximum damping ability appears when it is in a resonant vibrating frequency.
However, the damping ability of such form is not so greatly important in its function in view of a vibration preventing alloy.
Historical form is a damping form produced due to those courses of stress/strain deformation rates in case of applying a stress from exterior and removing said stress are different each other, and at this moment, an energy as much as corresponding to historical loss becomes a cause of damping.
Accordingly, the damping ability of this form has a property which has no relation with vibration frequency but greatly depends on the transformation amplitude.
Since such historical form has a case of showing up a great damping ability regardless of vibration frequency, it may have a vibration preventing effect industrially.